The present invention relates to a liquid crystal display apparatus and a method for manufacturing the same, and in particular to a liquid crystal display apparatus which has contact holes in an insulating layer covering switching elements, and a method for manufacturing the liquid crystal display apparatus.
In recent years, in the field of information processing apparatuses mainly including computers, and the field of video processing apparatus mainly including television sets, lightweight and small-sized liquid crystal display apparatuses which can display an image or a video image in detail have been developed.
Nowadays, most commonly-used liquid crystal display apparatuses comprise two sheets of glass substrate having a plurality of electrodes and a liquid crystal layer between the glass substrates. For example, in a color active matrix type liquid crystal apparatus, a matrix array substrate, which is a first substrate, is provided with a switching element such as a thin film transistor whose amorphous silicon or polysilicon is a semiconductor layer, or the like, and a pixel electrode, a scanning line and a signal line which are connected to the switching element. On the other hand, a counter substrate, which is a second substrate, is provided with a color filter including colored layers corresponding to the three primary colors, and a counter electrode. Also, these two substrates are fixed to each other with an adhesive formed on peripheral portions of the substrates through a spacer for keeping the distance therebetween constant.
In recent years, in order to relax the pasting accuracy between the substrates and improve the aperture ratio, an insulating layer comprising a color filter layer or a transparent resin is ordinarily arranged between the switching element and the pixel electrode on the matrix array substrate. In this case, for electrically connecting the switching element and the pixel element, it is necessary to form a contact hole in the insulating layer.
However, there is a likelihood that the following disadvantages may occur due to the existence of the contact hole. That is, dust may attach to an inside wall of a recess of the contact hole, thereby reducing the reliability of the liquid crystal display apparatus. Also, printing properties of an alignment film for orienting the liquid crystals may deteriorate to cause an uneven display.
The present invention has been made in order to solve the above problems, and an object thereof is to provide a liquid crystal display apparatus which has a good display quality and a high reliability, and a method for manufacturing the liquid crystal display apparatus.
An aspect of the present invention is a liquid crystal display apparatus comprising: an array substrate including a first substrate, a switching element formed on the first substrate, an interlayer insulating film formed so as to cover the switching element, a pixel electrode formed on the interlayer insulating film and connected to the switching element via a contact hole formed in the interlayer insulating film, an alignment film formed so as to cover the pixel electrode, and a spacer formed under the alignment film;
a counter substrate arranged so as to oppose the array substrate; and
liquid crystal composition arranged between the array substrate and the counter substrate,
wherein a flattening layer made with the same material as that of the spacer is arranged between the pixel electrode and the alignment film within a region corresponding to the contact hole.
Also, another aspect of the present invention is a method for manufacturing a liquid crystal apparatus where a liquid crystal layer is sandwiched between a first substrate and a second substrate, comprising the steps of:
forming a switching element on the first substrate;
forming an interlayer insulating film having a contact hole corresponding to one portion of the switching element and covering the switching element;
forming a pixel electrode connected to the switching element via the contact hole on the interlayer insulating film;
forming a spacer and simultaneously forming a flattening layer within a region corresponding to the contact hole;
forming an alignment film after formation of the flattening layer; and
performing a rubbing process on the alignment film.
According to the present invention, the contact hole is fattened by the flattening layer, so that dust can be prevented from adhering to the inside of the contact hole and the printing property of the alignment film can be improved. Accordingly, it becomes possible to provide a liquid crystal display apparatus which has an excellent display quality and a high reliability.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.